Conclusion
If you read this Guitarity, I guess your heart will sink into your boots when thinking of establishing an ensemble. All those things which can go wrong while you do not sense them! All those annoyances which spread in secret!
I don't think that you do not sense anything: in many cases you sense more than you talk about or even want to know. In that case you are up to a real problem: dou you feel sufficiently safe in the ensemble to say what's on your mind? Are you possibly afraid that you will loose an activity you love -playing together is real fun!- if you speak up about an obstacle or annoyance?
Merciless practice is, that unspoken annoyances do far more damage than the ones you have talked over. Unspoken annoyances tend to grow with time.
My conclusion is that inside an ensemble communication around/outside the music is equally important as communication inside the music. This is -for me at least- a sigh around the saying It's too late to lock the stable door after the horse has bolted.
As a musician, never keep yourself from establishing or participating in an ensemble: its price is fabulous, a whole which is more than the sum of the participants!
Be assertive and communicate in a respectful manner about the things which are bothering you in the ensemble, and cooperate to correct them. Playing together is more than playing your part like you are the soloist. In order to do that right you will have to communicate both inside and outside the music. This implies both speaking and listening carefully!
This will prevent most annoyances and will render this Guitarity obsolete!